I really, really like this girl. Wow, I've never been attracted to someone so much in my life. Not to sound corny, but she's just awesome.
She's dating someone and I'm just too shy to really talk to her. The guy that she's dating seems perfect for her. They're both just really nice people... they seem kind of flawless... and it seems like they'll never break up.
Give up on it for now. Maybe try to pick her up on the rebound if they break up.
What >>2 said, and in the meantime use this as an opportunity to look at yourself...what makes you think that the guy she's dating is flawless? What does he have that you don't? If it's something that you can change, then go for it!
What kind of person is she? sometimes you can tell how long their relationships are going to be if you just watch them, and what clique they're in.
I'd say just become friends with her. I recommend against trying to come inbetween them, though. Trust me on this one. （´∀｀）
become friends but not really really close friends. if you get too close then you wont really be considered for the rebound.